Touch display device and fabrication method thereof

ABSTRACT

The present application provides a touch display panel having a display module, a touch module, and a plurality of pads located in a peripheral area. The pads include a first pad pattern and a second pad pattern located above the first pad pattern, the second pad pattern covers a top surface of the first pad pattern and exposes sidewalls of the first pad pattern, and the first pad pattern and the second pad pattern are formed in a same etching step.

FIELD OF INVENTION

The present application relates to a field of touch display technology,and more particularly to a touch display device and a fabrication methodthereof.

BACKGROUND

In a known organic light-emitting diode on-cell touch display (OLEDon-cell touch) technology, also known as direct on-cell touch (DOT)technology, integration of display and touch control is realized bydirectly forming a touch control structure using low-temperature process(with a temperature less than or equal to 90° C.) over a thin-filmencapsulation (TFE) in an OLED panel. In a pad structure of a touchdisplay device, a first pad layer 1 is formed by a material ofsource/drain metal layers. In order to achieve a better bonding effect,a top surface and sidewalls of the first pad layer 1 are exposed. Asshown in FIG. 1, the source/drain metal layers will be over etched whenan etching is performed to an anode layer of the organic light emittingdiode display panel so that a cavity la appears on the sidewall of thefirst pad layer 1. When a material of the anode layer is ITO/Ag/ITO, itwill also cause precipitation of the Ag. A gap exists between a secondpad layer 2 and the first pad layer 1 when the second pad layer 2 issubsequently formed on the first pad layer 1, and electrochemicalcorrosion easily appears in this position after long term operation ofthe panel, thereby leading to failure of the panel.

Technical Problem

In view of this, the purpose of the present application is to provide atouch display device and a fabrication method thereof, which can improvethe side etching problem of the pad, thereby improving reliability ofthe panel.

Technical Solution

An embodiment of the present application provides a touch display panelhaving a stacked display module and a touch module, comprising: aplurality of pads located in a peripheral area, the pads comprises afirst pad pattern and a second pad pattern located above the first padpattern that is electrically connected to the first pad pattern, thesecond pad pattern covers a top surface of the first pad pattern andexposes sidewalls of the first pad pattern, the first pad pattern andthe second pad pattern are formed in a same etching step, the first padpattern and source/drain electrodes of the display module are in thesame layer, and the second pad pattern and a touch pattern of the touchmodule are in the same layer.

In one embodiment, the touch module comprises a first touch patternlayer and a second touch pattern layer, the first touch pattern layer isdisposed between the second touch pattern layers and the display module,and the second pad pattern and the second touch pattern layer are in thesame layer.

In one embodiment, the touch module of the touch display device is asingle-layered bridge touch structure, and the second pad pattern and atouch driving electrode and a touch sensing electrode of the touchmodule are in the same layer.

In one embodiment, the first pad pattern and the second pad pattern aremade of the same material.

In one embodiment, the pad further comprises a third pad patternelectrically connected to the second pad pattern, and the second padpattern is located between the first pad pattern and the third padpattern, and the third pad pattern and the first pad pattern are in thesame layer.

In one embodiment, the sidewalls of the bonding pad are covered by anorganic protective layer.

In one embodiment, the touch display device further comprises aninorganic layer disposed between two adjacent pads.

In one embodiment, the touch display device further comprises aninorganic layer and an organic protective layer disposed between twoadjacent pads, and the organic protective layer covers the sidewalls ofthe pads and the inorganic layer.

The present application provides a fabrication method of a touch displaydevice, wherein the touch display device comprises a stacked displaymodule and a touch module, the touch display device comprises aplurality of pads located in a peripheral area, the fabrication methodcomprising following steps:

providing a substrate, forming a source/drain metal layer on thesubstrate, and patterning the source/drain metal layer to form a firstpre-pad pattern and a source/drain;

forming an anode metal layer on the patterned source/drain metal layer,patterning the anode metal layer, and forming an anode and removing theanode metal layer above the first pre-pad pattern;

forming a touch material layer above the first pre-pad pattern,patterning the touch material layer to form a second pad pattern and atouch pattern, wherein the second pad pattern is located on the firstpre-pad pattern and exposes sidewalls of the first pre-pad pattern; and

etching the first pre-pad pattern to form a first pad pattern, whereinthe first pad pattern and the second pad pattern are electricallyconnected to form a solder pad.

In one embodiment, in the step of forming a touch material layer abovethe first pre-pad pattern, patterning the touch material layer to form asecond pad pattern and a touch pattern, an over etching issimultaneously performed to the first pre-pad pattern to form the firstpad pattern.

In one embodiment, the touch module comprises a first touch patternlayer and a second touch pattern layer, and the first touch patternlayer is disposed between the second touch pattern layer and the displaymodule, the second pad pattern and the second touch pattern layer are inthe same layer.

In one embodiment, the touch module of the touch display device is asingle-layer bridge touch structure, and the second pad pattern and atouch driving electrode and a touch sensing electrode of the touchmodule are in the same layer.

In one embodiment, the first pad pattern and the second pad pattern aremade of the same material.

In one embodiment, in the step of forming a touch material layer abovethe first pre-pad pattern, patterning the touch material layer to form asecond pad pattern and a touch pattern, two layers of touch material aresequentially formed above the first pre-pad pattern, and the two layersof touch material are patterned to respectively form stacked second andthird pad patterns.

In one embodiment, the fabrication method of the touch display devicefurther comprises forming an organic protective layer covering thesidewalls of the pad.

In one embodiment, the step of forming a touch material layer above thefirst pre-pad pattern, patterning the touch material layer to form asecond pad pattern and a touch pattern further comprises forming aninorganic material layer on the substrate, patterning the inorganicmaterial layer, and removing the inorganic material layer above andaround the first pre-pad pattern to form an inorganic layer.

In one embodiment, the step of forming a touch material layer above thefirst pre-pad pattern, patterning the touch material layer to form asecond pad pattern and a touch pattern further comprises forming aninorganic material layer on the substrate, patterning the inorganicmaterial layer, and removing the inorganic material layer above andaround the first pre-pad pattern to form an inorganic layer, wherein theinorganic layer and the organic protective layer are disposed betweenthe two adjacent pads, and the organic protective layer covers thesidewalls of the pads and the inorganic layer.

Advantageous Effects

Compared with the prior art, the touch display device and thefabrication method thereof of the present application utilize a touchpattern layer of a touch module together with a source/drain metal layerto form a pad. In a case where a second pad pattern is formed above thepad, sidewalls of the first pad pattern that are defective such as holesgenerated in the process of forming an anode of an organiclight-emitting unit are removed by etching, thereby preventingelectrochemical corrosion in the holes and improving reliability of thetouch display device.

BRIEF DESCRIPTION OF DRAWINGS

To detailly explain the technical schemes of the embodiments or existingtechniques, drawings that are used to illustrate the embodiments orexisting techniques are provided. Apparently, the illustratedembodiments are just a part of those of the present disclosure. It iseasy for any person having ordinary skill in the art to obtain otherdrawings without labor for inventiveness.

FIG. 1 is a schematic cross-sectional view of a pad of a touch displaydevice in the prior art.

FIG. 2 is a schematic structural diagram of a touch display deviceaccording to an embodiment of the application.

FIG. 3 is a schematic plan view of a touch module of the touch displaydevice according to an embodiment of the application.

FIG. 4 is a schematic plan view of the touch display device according toan embodiment of the application.

FIG. 5 is a schematic cross-sectional view of a pad of the touch displaydevice according to an embodiment of the application.

FIG. 6 is a schematic plan view of the pad of the touch display deviceaccording to an embodiment of the application.

FIG. 7 is a schematic cross-sectional view of a pad of a touch displaydevice according to another embodiment of the application.

FIG. 8a to 8f are schematic cross-sectional views of a fabricationmethod of a touch display device according to an embodiment of theapplication.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present applicationwill be described clearly and completely with reference to the drawingsin the embodiments of the present application. Obviously, the describedembodiments are only a part of the embodiments of the presentapplication, but not all the embodiments. Based on the embodiments inthe present application, all other embodiments obtained by those skilledin the art without making creative work fall within the protection scopeof the present application.

Please refer to FIG. 2. The first embodiment of the present applicationprovides a touch display device 100. The touch display device 100comprises a display module 10 and a touch module 20 that are stacked.The display module 10 comprises an array substrate 11, a plurality oforganic light emitting units 12 disposed on the array substrate 11, anda thin film encapsulation layer 13 for encapsulating the plurality oforganic light emitting units 12. The organic light emitting units 12comprise an anode, a cathode, and an organic light emitting layerdisposed between the anode and the cathode. Among them, a material ofthe anode may be a material commonly used in the field, for example, astack of ITO-Ag-ITO. The touch module 20 is directly formed on the thinfilm encapsulation layer 13 by using a low temperature process (of atemperature less than or equal to 90° C.) to realize an integration ofdisplay and touch.

Please refer to FIG. 3, the touch module 20 comprises a first touchpattern layer 20 a and a second touch pattern layer 20 b. The firsttouch pattern layer 20 a is disposed between the second touch patternlayer 20 b and the display module 10. In one embodiment, the touchmodule 20 of the touch display device 100 is a single-layered bridgetouch structure. Please refer to FIG. 2 and FIG. 3, a specificconfiguration of the single-layered bridge touch structure will bedescribed below. The touch module 20 comprises a bridge electrode 21disposed on the thin film encapsulation layer 13, a plurality of firsttouch patterns 22 disposed along a first direction D1, a plurality ofsecond touch patterns 23 disposed along a second direction D2, and aplurality of connecting electrodes 24 configured to connect two adjacentsecond touch patterns 23. Herein, the plurality of first touch patterns22, the plurality of second touch patterns 23, and the plurality ofconnecting electrodes 24 are located in a same layer and are locatedabove the bridge electrodes 21 and are insulated from the bridgeelectrodes 21 by an insulating layer 25. That is, the first touchpattern layer 20 a comprises the bridge electrode 21. The second touchpattern layer 20 b comprises the first touch pattern 22, the secondtouch pattern 23, and the connection electrode 24. Two adjacent firsttouch patterns 22 are connected to the same bridge electrode 21 througha through hole 25 a in the insulating layer 25. One of the first touchpatterns 22 or the second touch patterns 23 is a touch drivingelectrode, and the other is a touch sensing electrode. In oneembodiment, the first direction D1 and the second direction D2 areperpendicular to each other. The first touch pattern 22 and the secondtouch pattern 23 are formed in a diamond shape. In other embodiments,the first touch pattern 22 and the second touch pattern 23 may also beformed in other shapes such as a long strip. A material of the firsttouch pattern layer 22 and the second touch pattern 23 can be indium tinoxide (ITO), or gold, silver, copper, lithium, sodium, potassium,magnesium, aluminum, zinc and combinations thereof to form a metal meshshape. A material of the bridge electrode 21 may be indium tin oxide, ora metal such as a single layer or a stack of copper, silver, molybdenum,aluminum, or molybdenum. In the present embodiment, materials of thefirst touch pattern layer 20 a and the second touch pattern layer 20 bare both stacked layers of titanium/aluminum/titanium.

The touch module 20 of the present application is not limited to theabove-mentioned structure. In other embodiments of the presentapplication, the touch driving electrodes and the touch sensingelectrodes of the touch module 20 are located in different layers. Thatis, the first touch pattern layer 20 a comprises one of the touch driveelectrode or the touch sensing electrode, and the second touch patternlayer 20 b comprises the other of the touch drive electrode or the touchsensing electrode.

Referring to FIG. 4, the touch display device 100 can be divided into adisplay area AA and a peripheral area NAA surrounding the display areaAA. A plurality of pads 40 are provided in the peripheral area NAA. Thepads 40 are configured to connect a display element or a touch elementin the touch display device 100 with any signal, for example,electrically connected with a driving chip (IC) through a flexiblecircuit board (FPC), or directly electrically connected with a chip onfilm (COF). In addition, the application does not limit the type andfunction of the pads 40. The pads 40 may be gate bonding pads, sourcebonding pads, or test bonding pads. They may also be configured asbonding pads of the touch module 20 to electrically connect the touchmodule 20 and a touch driving chip.

Please refer to FIG. 5 and FIG. 6, the pads 40 comprise a first padpattern 41 and a second pad pattern 42 located above the first padpattern 41. The first pad pattern 41 and the second pad pattern 42 areelectrically connected to form the pad 40 of the present application.The second pad pattern 42 covers a top surface of the first pad pattern41 but does not cover sidewalls 41 a of the first pad pattern. In otherwords, the second pad pattern 42 exposes sidewalls 41 a of the first padpattern.

The first pad pattern 41 and the second pad pattern 42 are formed by thesame etching step. In one embodiment, in order to simplify thefabrication process, the first pad pattern 41 is over-etched in anetching step of the second pad pattern 42. In other embodiments, thesecond pad pattern 42 may be etched first, and then sidewalls of thelower metal layer not covered by the second pad pattern 42 may beremoved to form the first pad pattern 41.

The present application does not limit a shape of the pads 40. In thisembodiment, the pads 40 are formed in a trapezoidal cross section, andthe first pad pattern 41 and the second pad pattern 42 are respectivelyformed in a trapezoidal cross section. Top and bottom surfaces of thefirst pad pattern 41 and the second pad pattern 42 are rectangular. Inother embodiments, the top and bottom surfaces of the first pad pattern41 and the second pad pattern 42 may also be circular, triangular,polygonal, or other irregular shapes.

The array substrate 11 of the display module 10 comprises a drivingcircuit of the display module 10, and the driving circuit comprises aplurality of thin film transistors. The first pad pattern 41 andsource/drain electrodes of the thin film transistor are formed in thesame layer. It can be understood that the first pad pattern 41 can befabricated by using the same material as the source/drain electrodes ofthe thin film transistor in the same process. The first pad pattern 41may be formed using materials used as the source/drain electrodes in theart, for example, using a stack of copper (Cu) and molybdenum (Mo), astack of copper (Cu) and molybdenum titanium (MoTi) alloy, a stack ofcopper (Cu) and titanium (Ti), a stack of aluminum (Al), molybdenum(Mo), and copper-niobium (CuNb) alloy. In the present embodiment, thematerial of the first pad pattern 41 is a stack oftitanium/aluminum/titanium.

The second pad pattern 42 and the touch pattern in the touch module 20are in the same layer. It can be understood that the second pad pattern42 and the touch pattern in the touch module 20 can be fabricated byusing the same material in the same manufacturing process. The touchpattern here refers to electrodes configured to provide touch control inthe touch module 20, for example, touch driving electrodes, touchsensing electrodes, or bridge electrodes, which may be included in anyone of the first touch pattern layer or the second touch pattern layer.From the perspective of simplifying the fabrication, the second padpattern 42 and the second touch pattern layer 20 b are formed in thesame layer, that is, in the same layer with the touch pattern layer faraway from the display module 10. In the present embodiment, the secondpad pattern 42 and the touch driving electrodes and touch sensingelectrodes in the touch module 20 are in the same layer. In otherembodiments of the present application, the second pad pattern 42 andthe bridge electrode in the touch module 20 may also in the same layer.

In consideration of reducing impedance and simplifying the fabrication,materials of the first pad pattern 41 and the second pad pattern 42 arethe same. That is, in the present embodiment, the material of the secondpad pattern 42 is a stack of titanium/aluminum/titanium. There is nostep formed between the first pad pattern 41 and the second pad pattern42. Specifically, sidewalls 41 a of the first pad pattern 41 and thesecond pad pattern 42 are connected to sidewalls 42 a of the second padpattern 42 and are located in the same plane. A bottom surface of thesecond pad pattern 42 has the same shape and size as a top surface ofthe first pad pattern 41, which completely overlaps thereof.

In other embodiments of the present application, the touch module 20 isnot a touch module with a single-layer bridge structure. For example,the touch module 20 comprises a plurality of touch driving electrodesand a plurality of touch sensing electrodes. The touch drivingelectrodes are disposed in the same layer. The touch sensing electrodesare disposed in the same layer. The touch driving electrodes and thetouch sensing electrodes are located in different layers to togetherform a matrix-type projected capacitor. At this time, the second padpattern 42 and one of the touch driving electrode or the touch sensingelectrode in the touch module 20 are disposed in the same layer.

The touch display device 100 may further comprise an inorganic layer 60disposed between two adjacent pads 40. The inorganic layer 60 and theinsulating layer 25 disposed between the first touch pattern layer 20 aand the second touch pattern layer 20 b are in the same layer and areformed in the step of forming the insulating layer 25. It can beretained or removed.

In addition, in order to achieve a better bonding, the surface andsidewalls of the pads 40 may be exposed. In some embodiments, thesidewalls of the pads 40 are the sidewalls 41 a of the first pad patternand the sidewalls 42 a of the second pad pattern may also be covered byan organic protective layer 70. The organic protective layer 70 may onlybe provided around the sidewalls 41 a of the first pad pattern and thesidewalls 42 a of the second pad pattern, or may be filled between twoadjacent pads 40. The organic protective layer 70 and an organicprotective layer 26 covering the second touch pattern layer 20 a may bein the same layer.

In one embodiment, the inorganic layer 60 is covered by the organicprotective layer 70.

Referring to FIG. 7, in another embodiment of the present application,the pads 40 further comprise a third bonding pad pattern 43 electricallyconnected to the second bonding pad pattern 42. The second pad pattern42 is disposed between the first pad pattern 41 and the third padpattern 43. The third pad pattern 43 and the first touch pattern 20 aare in the same layer, and its material may be the same as the first padpattern 41 and the second pad pattern 42.

Please refer to FIGS. 8a to 8 f, the second embodiment of the presentapplication also provides a fabrication method of the touch displaydevice 100, comprising following steps:

Step S1: providing a substrate 200, forming a source/drain metal layeron the substrate 200, and patterning the source/drain metal layer toform a first pre-pad pattern 410 located in a peripheral area NAA of thetouch display device 100 (please refer to FIG. 4) and a source/drain(not shown) of the display area AA of the touch display device 100. Themethod of patterning the source/drain metal layer may bephotolithography.

S2: forming an anode metal layer 50 on the patterned source/drain metallayer, patterning the anode metal layer 50, forming an anode of anorganic light emitting diode located in the display area AA and removingthe anode metal layer 50 above the first pre-pad pattern 410.Specifically, all the anode metal layer 50 disposed in the peripheralarea AA may be removed, or only the anode metal layer 50 above the firstpre-pad pattern 410 may be removed, which is not limited in thisapplication. In this step, when the anode metal layer is etched, thefirst pre-pad pattern 410 is over-etched to form a hole 41 a onsidewalls thereof. When the material of the anode metal layer is a stackof ITO-Ag-ITO, defects such as Ag precipitation may also occur.

S3: forming a touch material layer above the first pre-pad pattern 410,patterning the touch material layer, and forming a second pad pattern 42and a touch pattern (not shown) located in the display area AA of thetouch display device 100. The second pad pattern 42 is disposed abovethe first pre-pad pattern 410 and exposes the sidewalls of the firstpre-pad pattern 410. As shown in FIG. 8 d, the second pad pattern 42partially covers the top surface of the first pre-pad pattern 410. Asdescribed in the first embodiment, the touch pattern can be a touchdriving electrode, a touch sensing electrode, or a bridge electrode. Thespecific situation has been explained in the first embodiment, and willnot be repeated here.

In this step, it may further comprise a step of forming an inorganicmaterial layer on the substrate 200, patterning the inorganic materiallayer, and removing the inorganic material layer above and around thefirst pre-pad pattern 410 to form an inorganic layer 60. Herein, theinorganic layer 60 is disposed between two first pre-pad patterns 410.The inorganic material layer is the same layer as the insulating layer25 disposed between the first touch pattern layer 20 a and the secondtouch pattern layer 20 b, and is made in the same step. This step is toremove the insulation barrier between the first pad pattern 41 and thesecond pad pattern 42. In other methods, the inorganic material layermay be completely removed by patterning.

S4: etching the first pre-pad pattern 410 to form the first pad pattern41. The first pad pattern 41 and the second pad pattern 42 areelectrically connected to form the pad 40 of the present application. Inthis step, the defective sidewalls 41 a of the first pre-pad pattern 410having holes and the like are removed by etching.

In this embodiment, in order to simplify the fabrication, in step S3,forming a touch material layer on the first pre-pad pattern 410,patterning the touch material layer, and forming the second pad pattern42 and the touch pattern. In this process, the first pre-pad pattern 410is simultaneously over-etched to form the first pad pattern 41. In otherwords, step S4 and step S3 can be the same step.

In other embodiments, an etching can be performed first to form thesecond pad pattern 42, and then etching the sidewalls of the firstpre-pad pattern 410 that are not covered by the second pad pattern 42 toform the first pad pattern 41. The other features of the pad 40 havebeen described in detail in the first embodiment and will not berepeated again.

In addition, referring to FIG. 8 f, after step S4, a step S5 may befurther included: forming an organic protective layer 70 covering thesidewalls of the pads 40. The organic protective layer 70 is filledbetween two adjacent pads 40. The organic protective layer 70 may onlybe provided around the sidewalls 41 a of the first pad pattern and thesidewalls 42 a of the second pad pattern, or may be filled between twoadjacent pads 40. The organic protective layer 70 can be made in thesame layer as an organic protective layer 26 covering the second touchpattern layer 20 a and made in the same step. The inorganic layer 60 mayalso be covered by the organic protective layer 70.

In addition, the specific structure of the touch display device 100,such as the display module 10 and the touch module 20, have beendescribed in the first embodiment, and will not be repeated again.

In another embodiment of the present application, when fabricating thetouch display device 100 as shown in FIG. 7, in step S3, two touchmaterial layers are sequentially formed on the first pre-pad pattern410, and the two touch material layers are patterned to respectivelyform a second pad pattern 42 and a third pad pattern 43 that arestacked, and a touch pattern (not shown) in the display area AA of thetouch display device 100. Step S4 is next performed: etching the firstpre-pad pattern 410 to form the first pad pattern 41. The first padpattern 41, the second pad pattern 42, and the third pad pattern 43 areelectrically connected to form the pads 40 of the present application.

Compared with the prior art, the touch display device and thefabrication method thereof of the present application utilize a touchpattern layer of a touch module together with a source/drain metal layerto form a pad. In a case where a second pad pattern is formed above thepad, sidewalls of the first pad pattern that are defective such as holesgenerated in the process of forming an anode of an organiclight-emitting unit are removed by etching, thereby preventingelectrochemical corrosion in the holes and improving a reliability ofthe touch display device.

The descriptions of the above embodiments are only used to helpunderstand the technology of the present application, solutions andtheir core ideas; those of ordinary skill in the art should understandthat they can still modify the technical solutions described in theforegoing embodiments or equivalently replace some of the technicalfeatures, and these modifications or replacements do not make theessence of the corresponding technical solutions deviate from the scopeof the technical solutions of the embodiments of the presentapplication.

What is claimed is:
 1. A touch display device having a stacked displaymodule and a touch module, comprising: a plurality of pads located in aperipheral area, wherein the pads comprise a first pad pattern and asecond pad pattern located above the first pad pattern that iselectrically connected to the first pad pattern, the second pad patterncovers a top surface of the first pad pattern and exposes sidewalls ofthe first pad pattern, the first pad pattern and the second pad patternare formed in a same etching step, the first pad pattern andsource/drain electrodes of the display module are in a same layer, andthe second pad pattern and a touch pattern of the touch module are in asame layer.
 2. The touch display device of claim 1, wherein the touchmodule comprises a first touch pattern layer and a second touch patternlayer, the first touch pattern layer is disposed between the secondtouch pattern layer and the display module, and the second pad patternand the second touch pattern layer are in the same layer.
 3. The touchdisplay device of claim 2, wherein the touch module of the touch displaydevice is a single-layered bridge touch structure, and the second padpattern and a touch driving electrode and a touch sensing electrode ofthe touch module are in the same layer.
 4. The touch display device ofclaim 1, wherein the first pad pattern and the second pad pattern aremade of a same material.
 5. The touch display device of claim 2, whereinthe pad further comprises a third pad pattern electrically connected tothe second pad pattern, the second pad pattern is located between thefirst pad pattern and the third pad pattern, and the third pad patternand the first pad pattern are in the same layer.
 6. The touch displaydevice of claim 1, wherein sidewalls of the pads are covered by anorganic protective layer.
 7. The touch display device of claim 1,further comprising an inorganic layer disposed between two adjacentpads.
 8. The touch display device of claim 1, wherein the touch displaydevice further comprises an inorganic layer and an organic protectivelayer disposed between two adjacent pads, and the organic protectivelayer covers sidewalls of the pads and the inorganic layer.
 9. Afabrication method of a touch display device, wherein the touch displaydevice comprises a stacked display module and a touch module, andfurther comprises a plurality of pads located in a peripheral area, andthe fabrication method comprises following steps: providing a substrate,forming a source/drain metal layer on the substrate, and patterning thesource/drain metal layer to form a first pre-pad pattern and asource/drain; forming an anode metal layer on the patterned source/drainmetal layer, patterning the anode metal layer, and forming an anode andremoving the anode metal layer above the first pre-pad pattern; forminga touch material layer above the first pre-pad pattern, patterning thetouch material layer to form a second pad pattern and a touch pattern,wherein the second pad pattern is located on the first pre-pad patternand exposes sidewalls of the first pre-pad pattern; and etching thefirst pre-pad pattern to form a first pad pattern, wherein the first padpattern and the second pad pattern are electrically connected to formthe pads.
 10. The fabrication method of the touch display deviceaccording to claim 9, wherein in the step of forming the touch materiallayer above the first pre-pad pattern, patterning the touch materiallayer to form the second pad pattern and the touch pattern, over-etchingis simultaneously performed to the first pre-pad pattern to form thefirst pad pattern.
 11. The fabrication method of the touch displaydevice according to claim 9, wherein the touch module comprises a firsttouch pattern layer and a second touch pattern layer, the first touchpattern layer is disposed between the second touch pattern layer and thedisplay module, and the second pad pattern and the second touch patternlayer are in a same layer.
 12. The fabrication method of the touchdisplay device according to claim 11, wherein the touch module of thetouch display device is a single-layer bridge touch structure, and thesecond pad pattern and a touch driving electrode and a touch sensingelectrode of the touch module are in the same layer.
 13. The fabricationmethod of the touch display device according to claim 9, wherein thefirst pad pattern and the second pad pattern are made of a samematerial.
 14. The fabrication method of the touch display deviceaccording to claim 9, wherein in the step of forming the touch materiallayer above the first pre-pad pattern, patterning the touch materiallayer to form the second pad pattern and the touch pattern, two layersof touch material are sequentially formed above the first pre-padpattern, and the two layers of touch material are patterned torespectively form stacked second and third pad patterns.
 15. Thefabrication method of the touch display device of claim 9, furthercomprising forming an organic protective layer covering sidewalls of thepads.
 16. The fabrication method of the touch display device accordingto claim 9, wherein in the step of forming the touch material layerabove the first pre-pad pattern, patterning the touch material layer toform the second pad pattern and the touch pattern, further comprisesforming an inorganic material layer on the substrate, patterning theinorganic material layer, and removing the inorganic material layerabove and around the first pre-pad pattern to form an inorganic layer.17. The fabrication method of the touch display device according toclaim 15, wherein in the step of forming the touch material layer abovethe first pre-pad pattern, patterning the touch material layer to formthe second pad pattern and the touch pattern, further comprises formingan inorganic material layer on the substrate, patterning the inorganicmaterial layer, and removing the inorganic material layer above andaround the first pre-pad pattern to form an inorganic layer, wherein theinorganic layer and the organic protective layer are disposed betweentwo adjacent pads, and the organic protective layer covers the sidewallsof the pads and the inorganic layer.